Eye Exam: What’s REALLY Happening During Your Visit

Eye exam essentials: what’s really happening and how to advocate for yourself

If you’ve ever wondered what actually happens during an eye exam, you’re not alone. In this conversation with ophthalmologist Dr. Radka Toms, we broke down the parts of an eye exam, why screening matters, and how to “know your numbers” so you can protect your sight.

Why a regular eye exam matters

A regular exam is more than reading letters on a chart. Screening catches silent problems early—especially glaucoma and diabetic changes—before symptoms show up. If you have a family history of eye disease, or you’re 40+, a routine exam becomes even more important. Dr. Radka shared that risk increases with age, and eye pressure concerns can sneak up on people who feel “fine” until vision loss appears.

Who does what in an eye exam?

Titles vary by country. In the UK, an ophthalmologist focuses on disease prevention and treatment (both conservative and surgical), while an optician/optometrist addresses vision correction. In other countries, roles can overlap: some ophthalmologists also do refraction, and many opticians sell glasses and contacts. Wherever you live, an eye exam should cover both how you see and how healthy your eye tissues are.

What to expect during an eye exam: the core tests

Visual acuity and refraction. This step checks how clearly you see and what lens power sharpens your vision.
Slit lamp exam. A biomicroscope lets the doctor examine the front and back of the eye in detail—cornea, iris, lens, retina, and optic nerve.
Intraocular pressure (IOP). You may know the air-puff, but Dr. Radka prefers Goldmann applanation tonometry (a brief, numbed contact method) because it’s the gold standard. Corneal thickness changes the reading: a thick cornea can make pressure look higher; a thin cornea can make it look lower (this is especially relevant if you’ve had LASIK). Around 550 micrometers is a typical reference.
OCT (Optical Coherence Tomography). Think of this scan like ultrasound that uses light. It’s safe for kids and adults and shows cross-section images of the optic nerve and macula. Done yearly or every other year, OCT lets the clinic track stability or progression.
Visual field test. This test maps side vision. It can be tricky for very elderly patients, but it’s critical when glaucoma is suspected and can even reveal certain neurological patterns.

Dilation during an eye exam: when and why

On a first visit, dilation is often part of a thorough exam so the doctor can see the whole retina and the full lens. The drops used are mild (not atropine for adults). If light is uncomfortable, ask for a smaller, dimmer beam—you can ask for that. Ongoing dilation depends on your situation: diabetics and many retinal conditions require it regularly; for a healthy routine check, it’s not always needed every time.

Cataracts: when to consider surgery

An eye exam helps distinguish where blur is coming from—cornea, lens (cataract), vitreous, or retina. Cataracts come in different patterns (for example, nuclear sclerotic in the center, cortical “spokes,” or a dense posterior subcapsular spot). Surgery is a balance of risks and benefits. Many people are guided by function and measurements: if vision falls to around 20/40 (often tied to legal driving standards), and other tissues are healthy, surgery can offer clear improvement. Rarely, an exam may reveal a different urgency—like a very small eye with a shallow chamber and dangerously high pressure—where removing the lens can prevent an acute attack.

“Know your numbers” from your eye exam

IOP target: an eye exam should confirm that pressure is not higher than 21 mmHg (younger adults are often 14–15).
Corneal thickness: thicker looks higher; thinner looks lower—context matters.
OCT trend: stable or progressing? Comparing the same machine over time helps.
Visual field: especially if OCT or the nerve looks suspicious.

Bring these up at your next eye exam so you leave with clear, trackable data.

Emergencies you should never ignore after an eye exam—or any day

Two red-flag situations need same-day ophthalmology attention:

Acute angle-closure signs: severely painful red eye, very blurry vision, hazy cornea, a big irregular pupil, and headache. Pressures can spike extremely high, and time matters.
Flashes + a “curtain.” Flashes of light followed by a dark curtain or patch sliding over part of your vision can signal a retinal detachment. Go straight to an eye doctor immediately.

Lifestyle context you can discuss at your eye exam

Light isn’t always the villain. In one example, an outdoorsy 80-year-old gardener had surprisingly clear lenses. More broadly, blood sugar control, exercise, family history, and overall metabolic health relate to risk patterns seen in clinic (for glaucoma, cataracts, and diabetic retinopathy). Your eye exam is a great moment to talk about these possible factors with your doctor.

Follow-up timing after an eye exam

If everything looks normal, pressure is fine, and the OCT is stable, some people return every two years (with a pressure check yearly). If anything looks borderline—or you have glaucoma, diabetes, or macular changes—your eye exam schedule will be more often, based on medical judgment.

Watch the episode of What’s REALLY Going On During Your Eye Exam?

Claudia Muehlenweg has helped thousands of people enhance their natural eyesight and overall well-being. She is deeply passionate about reconnecting clients with their purpose, confidence, and freedom.

Filed in: Eye Health, Vision Improvement